System and method for calibrating weak write test mode (wwtm)
AssigneeHewlett-Packard Development Company, L.P.
InventorsDonald Weiss, Richard Woodruff, John Wuu
Life of this patent
Estimating the term…
Abstract
According to at least one embodiment, a method comprises measuring drive current of a reference memory cell of a circuit, and determining, based on the measured drive current of the reference memory cell, a drive current to be supplied to a calibration memory cell of the circuit to mimic a defective memory cell. The method further comprises supplying the determined drive current to the calibration memory cell, and using the calibration memory cell to determine strength of a weak write to be utilized by a weak write test for detecting defective memory cells.
Claims26
A method of calibrating a Weak Write Test Mode (WWTM) comprising:
- measuring a drive current of a reference random access memory (RAM) cell;
- determining, based on the measured drive current of the reference RAM cell, a drive current to supply to a calibration RAM cell for mimicking a defective RAM cell;
- and
- using said calibration RAM cell to determine strength of a weak write for a WWTM test circuit to utilize for detecting defective RAM cells.
The method of claim 111 further comprising:
- determining a minimum strength of said plurality of different weak write strengths that was able to flip said bit of said calibration RAM cell;
- and
- selecting said minimum strength as said strength for said WWTM test circuit to utilize for detecting defective RAM cells.
A system for calibrating a WWTM testing process comprising:
- means for measuring drive current of a reference memory cell;
- means for determining, based at least in part on the measured drive current of the reference memory cell, a drive current for a calibration memory cell to mimic a defective memory cell;
- means for selectively adapting drive current of the calibration memory cell to be the determined drive current for mimicking a defective memory cell;
- and
- means for determining, based on the calibration memory cell having the determined drive current for mimicking a defective memory cell, a weak write strength for a WWTM circuit to utilize for detecting defective memory cells.
A computer program product having a computer readable medium having computer program logic recorded thereon for calibrating the strength of a weak write to be used by a weak write test for detecting defective memory cells in a circuit, the computer program product comprising:
- code for determining, based at least in part on a measured drive current of a reference memory cell of a circuit, a drive current for a calibration memory cell of the circuit to mimic a defective memory cell;
- code for generating control signals to selectively adapt the calibration memory cell's drive current to the determined drive current for mimicking a defective memory cell;
- and
- code for determining, based on the calibration memory cell having the adapted drive current for mimicking a defective memory cell, strength of a weak write to be utilized by a weak write test circuit for detecting defective memory cells in the circuit.
A method comprising:
- measuring drive current of a reference memory cell of a circuit;
- determining, based on the measured drive current of the reference memory cell, a drive current to be supplied to a calibration memory cell of the circuit to mimic a defective memory cell;
- supplying the determined drive current to the calibration memory cell;
- and
- using the calibration memory cell to determine strength of a weak write to be utilized by a weak write test for detecting defective memory cells.
Dependencies are inferred from the claim text.